Immunity (medicine)
In
Innate and adaptive
The
Innate immunity, also known as native immunity, is a semi-specific and widely distributed form of immunity. It is defined as the first line of defense against pathogens, representing a critical systemic response to prevent infection and maintain homeostasis, contributing to the activation of an adaptive immune response.[4] It does not adapt to specific external stimulus or a prior infection, but relies on genetically encoded recognition of particular patterns.[5]
Adaptive or acquired immunity is the active component of the host immune response, mediated by antigen-specific
Adaptive immunity can be acquired either 'naturally' (by infection) or 'artificially' (through deliberate actions such as vaccination). Adaptive immunity can also be classified as 'active' or 'passive'. Active immunity is acquired through the exposure to a pathogen, which triggers the production of antibodies by the immune system.[7] Passive immunity is acquired through the transfer of antibodies or activated T-cells derived from an immune host either artificially or through the placenta; it is short-lived, requiring booster doses for continued immunity.
The diagram below summarizes these divisions of immunity. Adaptive immunity recognizes more diverse patterns. Unlike innate immunity it is associated with memory of the pathogen.[5]
History of theories
For thousands of years mankind has been intrigued with the causes of disease and the concept of immunity. The prehistoric view was that disease was caused by supernatural forces, and that illness was a form of
Active immunotherapy may have begun with
The first clinical description of immunity which arose from a specific disease-causing organism is probably A Treatise on Smallpox and Measles ("Kitab fi al-jadari wa-al-hasbah″, translated 1848
Until the 19th century, the
The modern word "immunity" derives from the Latin immunis, meaning exemption from military service, tax payments or other public services.[10]
The first scientist who developed a full theory of immunity was Ilya Mechnikov[16] who revealed phagocytosis in 1882. With Louis Pasteur's germ theory of disease, the fledgling science of immunology began to explain how bacteria caused disease, and how, following infection, the human body gained the ability to resist further infections.[10]
In 1888
In Europe, the induction of active immunity emerged in an attempt to contain smallpox. Immunization has existed in various forms for at least a thousand years, without the terminology.[10] The earliest use of immunization is unknown, but, about 1000 AD, the Chinese began practicing a form of immunization by drying and inhaling powders derived from the crusts of smallpox lesions.[10] Around the 15th century in India, the Ottoman Empire, and east Africa, the practice of inoculation (poking the skin with powdered material derived from smallpox crusts) was quite common.[10] This practice was first introduced into the west in 1721 by Lady Mary Wortley Montagu[10] [the phrase "first introduced into the west in 1721 by lady Montagu" is quite not accurate and should be rendered "first promoted in the west, by lady Montague, in 1721". Because, as you can read here https://en.wikipedia.org/wiki/Variolation, the procedure was already known in Wales: "The method was first used in China, India, parts of Africa and the Middle East before it was introduced into England and North America in the 1720s in the face of some opposition. However, inoculation had been reported in Wales since the early 17th century"]. In 1798, Edward Jenner introduced the far safer method of deliberate infection with cowpox virus, (smallpox vaccine), which caused a mild infection that also induced immunity to smallpox. By 1800, the procedure was referred to as vaccination. To avoid confusion, smallpox inoculation was increasingly referred to as variolation, and it became common practice to use this term without regard for chronology. The success and general acceptance of Jenner's procedure would later drive the general nature of vaccination developed by Pasteur and others towards the end of the 19th century.[9] In 1891, Pasteur widened the definition of vaccine in honour of Jenner, and it then became essential to qualify the term by referring to polio vaccine, measles vaccine etc.
Passive immunity
Passive immunity is the immunity acquired by the transfer of ready-made
Naturally acquired passive immunity
A
Passive immunity is also provided through the transfer of
Artificially acquired passive immunity
Artificially acquired passive immunity is a short-term immunization induced by the transfer of antibodies, which can be administered in several forms; as human or animal blood plasma, as pooled human immunoglobulin for intravenous (
The artificial induction of passive immunity has been used for over a century to treat infectious disease, and before the advent of
Transfer of activated T-cells
Passive or "
Active immunity
When
Naturally acquired
Naturally acquired active immunity occurs as the result of an infection. When a person is exposed to a live pathogen and develops a primary immune response, this leads to immunological memory.[17] Many disorders of immune system function can affect the formation of active immunity, such as immunodeficiency[21] (both acquired and congenital forms) and immunosuppression.
Artificially acquired
Artificially acquired active immunity can be induced by a vaccine, a substance that contains antigen. A vaccine stimulates a primary response against the antigen without causing symptoms of the disease.[17] The term vaccination was coined by Richard Dunning, a colleague of Edward Jenner, and adapted by Louis Pasteur for his pioneering work in vaccination. The method Pasteur used entailed treating the infectious agents for those diseases, so they lost the ability to cause serious disease. Pasteur adopted the name vaccine as a generic term in honor of Jenner's discovery, which Pasteur's work built upon.
In 1807, Bavaria became the first group to require their military recruits to be vaccinated against smallpox, as the spread of smallpox was linked to combat.[22] Subsequently, the practice of vaccination would increase with the spread of war.
There are four types of traditional vaccines:[23]
- Inactivated vaccines are composed of micro-organisms that have been killed with chemicals and/or heat and are no longer infectious. Examples are vaccines against flu, cholera, plague, and hepatitis A. Most vaccines of this type are likely to require booster shots.
- Live, attenuated vaccines are composed of micro-organisms that have been cultivated under conditions which disable their ability to induce disease. These responses are more durable, however, they may require booster shots. Examples include yellow fever, measles, rubella, and mumps.
- Toxoids are inactivated toxic compounds from micro-organisms in cases where these (rather than the micro-organism itself) cause illness, used prior to an encounter with the toxin of the micro-organism. Examples of toxoid-based vaccines include tetanus and diphtheria.
- Subunit, recombinant, polysaccharide, and conjugate vaccines are composed of small fragments or pieces from a pathogenic (disease-causing) organism.[24] A characteristic example is the subunit vaccine against Hepatitis B virus.
In addition, there are some newer types of vaccines in use:
- Outer Membrane Vesicle (OMV) vaccines contain the outer membrane of a bacterium without any of its internal components or genetic material. Thus, ideally, they stimulate an immune response effective against the original bacteria without the risk of an infection.[25]
- which differ in the chemical form of nucleic acid and how it is delivered into host cells.
A variety of vaccine types are under development; see Experimental Vaccine Types.
Most vaccines are given by
Hybrid immunity
Hybrid immunity is the combination of natural immunity and artificial immunity. Studies of hybrid-immune people found that their blood was better able to neutralize the Beta and other variants of SARS-CoV-2 than never-infected, vaccinated people.[30] Moreover, on 29 October 2021, the Centers for Disease Control and Prevention (CDC) concluded that "Multiple studies in different settings have consistently shown that infection with SARS-CoV-2 and vaccination each result in a low risk of subsequent infection with antigenically similar variants for at least 6 months. Numerous immunologic studies and a growing number of epidemiologic studies have shown that vaccinating previously infected individuals significantly enhances their immune response and effectively reduces the risk of subsequent infection, including in the setting of increased circulation of more infectious variants. ..."[31]
See also
- Antiserum
- Antivenin
- Cell-mediated immunity
- Herd immunity
- Heterosubtypic immunity
- Hoskins effect
- Humoral immunity
- Immunology
- Inoculation
- Premunity
- Vaccine-naive
- Virgin soil epidemic
References
- ISBN 9780121983826.
- ^ Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Innate Immunity. Available from: https://www.ncbi.nlm.nih.gov/books/NBK26846/
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- ^ S2CID 14357403.
- ^ Janeway CA Jr, Travers P, Walport M, et al. Immunobiology: The Immune System in Health and Disease. 5th edition. New York: Garland Science; 2001. Glossary. Available from: https://www.ncbi.nlm.nih.gov/books/NBK10759/
- ^ "Immunity types". cdc.gov. Centers for Disease Control and Prevention (CDC). 2 November 2021.
- ^ a b Lindquester GJ (Spring 2006). "Introduction to the History of disease". Disease and Immunity. Rhodes College. Archived from the original on 2006-07-21.
- ^ a b c d e f g Silverstein AM (1989). History of Immunology (Hardcover). Academic Press – via Amazon.com.
- ^ a b c d e f g Gherardi E. "The Concept of Immunity. History and Applications". Immunology Course Medical School. University of Pavia. Archived from the original on 2007-01-02.
- ^ ISBN 2-87686-082-1.
- S2CID 239289426.
- ^ Chambers, Ephraim (1728). "Mithridate". History of Science: Cyclopædia. London. p. 561. Retrieved 4 October 2020.
- ^ Rāzī, Abū Bakr Muḥammad ibn Zakarīyā (1848). A Treatise on the Small-pox and Measles. Sydenham Society.
- ^ A "al-Razi". 2003 The Columbia Electronic Encyclopedia, Sixth Edition. Columbia University Press (from Answers.com, 2006.)
- ^ "The Nobel Prize in Physiology or Medicine 1908". NobelPrize.org.
- ^ a b c d e "Microbiology and Immunology On-Line Textbook". USC School of Medicine.
- ^ ISBN 978-0-8153-4101-7..
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- ^ "Variolation". Smallpox – A Great and Terrible Scourge. National Institutes of Health.
- ^ "Immunization: You call the shots". The National Immunization Program. U.S. Centers for Disease Control and Prevention. Archived from the original on 2006-09-29.
- ^ "Vaccine Types". www.vaccines.gov. Retrieved 2020-08-07.
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- ^ Staff (29 October 2021). "Science Brief: SARS-CoV-2 Infection-induced and Vaccine-induced Immunity". Centers for Disease Control and Prevention. Retrieved 12 November 2021.